Operation Koine was launched in April 2024 into A Milne Independent Funeral Directors in response to allegations of missing ashes and funeral plan fraud.
The company had an office in Glasgow and another in Dumbarton, West Dunbartonshire.
On Wednesday, officers from the Operation Koine team, with support from colleagues in North Wales, executed search warrants at an address in the Flint area of Wales.
A 58-year-old man and 38-year-old woman were subsequently rearrested.
On the same date, officers rearrested a 58-year-old woman in the Bishopbriggs area of East Dunbartonshire.
In an update on Thursday, Police Scotland said all three have now been charged in connection with the probe and will be reported to the Crown Office and Procurator Fiscal Service (COPFS) “in due course”.
Detective Superintendent Robert Bowie said: “I’d like to thank everyone who has come forward with information on this investigation and members of the public for their continued support.
“Operation Koine is an unprecedented investigation for Police Scotland and I want to reassure the public, our dedicated team have, and will, continue to work through all lines of enquiry.
“Anyone with additional information or concerns can still come forward and speak to us.”
In September, Police Scotland said it had received complaints from more than 70 people as part of the investigation.
Victim Support Scotland is working closely with the force to explore a package of support for anyone potentially affected.
A helpline is available on 0800 160 1985, with a webchat service at victimsupport.scot.
DS Bowie added: “A further drop-in clinic, where you can receive information and support, will be held on Friday 5 December.
“This is for people who have already been in contact with police around concerns, and information about the session will have been sent to you.”
Those with concerns that wish to get in touch with the inquiry team can call 101 or email Operationkoine@scotland.police.uk.
